Field
The invention relates generally to mask frame assemblies for making thin film semiconductor devices, and more particularly, to a mask frame assembly and a method of manufacturing the same which reduces the external shadow during a deposition process of manufacturing a display device and corresponding defects in the colors emitted by the pixels of the display.
Discussion of the Background
Organic light-emitting display devices generally include pixels each having a stacked structure including a pixel electrode as an anode, an opposite electrode as a cathode, and an emission layer between the pixel electrode and the opposite electrode. Images are displayed in color when holes and electrons, injected respectively from the anode and the cathode, recombine in the emission layer, thereby emitting light.
Each of the pixels may be a sub-pixel of one of, for example, a red pixel, a green pixel, and a blue pixel, and a desired color may be realized via a combination of these three color sub-pixels. In other words, each sub-pixel has a structure in which an emission layer that emits light of a red, green, or blue color is interposed between two electrodes, and color of a unit pixel is realized via an appropriate combination of the lights of these three colors.
The area of each sub-pixel is defined by a pixel defining layer, and the emission layer is formed within the defined area. The emission layer is generally formed using a deposition process. A mask frame assembly having the same pattern holes as the thin film pattern of an emission layer to be formed is arranged on a substrate. The thin film of an emission layer having a desired pattern is formed by depositing the raw material of the thin film onto the substrate via the pattern holes.
However, during the deposition process, the thin film pattern of the emission layer may not be accurately deposited within the area of the pattern holes of the mask frame assembly but may be deposited within the areas outside the pattern holes, and thus an external shadow may occur. The external shadow may cause color mixing between adjacent sub-pixels, and thus the resulting display product may have significant defects.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concepts, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.